1. Field
The following description relates to three-dimensional (3D) image display apparatuses and methods for selectively displaying a two-dimensional (2D) image and a 3D image.
2. Description of the Related Art
A three-dimensional (3D) image is observed according to the principle of stereoscopic vision, in which a person views an object with both eyes at the same time. Binocular parallax, a characteristic due to the positions of the left eye and right eye located about 65 mm apart from each other, is the most important factor producing a 3D image. Two categories of 3D image displays include displays using glasses and displays that do not use glasses. The latter generates 3D images by dividing images for left and right eyes without using glasses. Types of displays that do not use glasses include parallax barrier-type displays and lenticular-type displays.
A parallax barrier-type display alternately displays images to be seen respectively by the left and right eyes in the form of a vertical pattern or a photo using an extremely thin vertical lattice column, i.e., a barrier. By doing so, a vertical pattern image that is to be provided to the left eye and a vertical pattern image that is to be provided to the right eye are separated by the barrier and images from different viewpoints are seen by the left and the right eyes, respectively, so that a stereoscopic image is perceived.
The lenticular-type display arranges images corresponding to the left and right eyes on a focusing surface of a lenticular lens. When a user observes the images through the lenticular lens, the divided images are incident on the left and right eyes according to a directivity feature of the lens, so that a stereoscopic image is perceived.
According to both the parallax barrier-type display and the lenticular-type display, a period, a focal length, and a direction of the barrier or lens are fixed, and thus, locations at which 3D images may be observed are fixed. For example, the direction in which 3D images are observed is set according to the arrangement direction of the lenticular lens or the barrier, and thus, the 3D images may be seen in only one of a transverse mode and a longitudinal mode. However, various selections may be desired, for example, selection of a viewing direction or selection of 2D or 3D, due to the development of 3D image display devices.